This invention relates to rotary mechanisms, and, more particularly, to improved means for biasing apex seals in such mechanisms into good sealing engagement with the chamber walls of the mechanism.
Prior art of possible relevance includes the following U.S. Pat. Nos. 3,456,625 to Jones et al, issued July 22, 1969; 3,482,551 to Jones, issued Dec. 9, 1969; and 3,496,916 to Jones, issued Feb. 24, 1970.
During high speed operation, the apex seals of rotary engines of the trochoidal type may become overloaded by centrifugal force. Since such seals normally operate with very thin oil films, such excessive loads accelerate wear and thus engine failure.
As a consequence, there have been a number of proposals for cancelling out or reducing the effects of such centrifugal forces. The approaches taken heretofore required the use of numerous small counterweights, levers, or, in some cases, friction devices. The above identified patents are illustrative of such approaches.
While such proposals result in the unloading of the apex seals at high rotative speeds, because they require a number of parts, the service life and reliability is subject to some question. Moreover, because of the number of parts, such devices are expensive to manufacture and difficult to assemble.
Moreover, in other rotary mechanisms, not necessarily of the trochoidal type, there occasionally exists a need for means whereby the biasing pressure against apex seals may be simply varied at different points in a cycle of rotation.